This invention relates to a wheelchair which makes it possible for the handicapped with an extremely limited or no lower-limb function such as a paraplegic to change his or her posture from a seated posture to a stand-up posture and vice versa, using his or her push-up force (the body lift-up action of the handicapped by his or her upper limb) which he or she daily exercises, as the motive force, without using any external power.
The wheelchair is a kind of vehicle which is required to cover a range of motion substantially the same as walking and can be regarded as a short-distance transportation vehicle. Accordingly, the wheelchair must have a full function as a daily instrument, a moving function and a function which makes it possible for the handicapped to carry out work by use of the wheelchair. However, in accordance with the conventional wheelchair, the user of the wheelchair can do the work only in the seated posture but cannot do work which can be done only in a stand-up posture because his or her hands cannot reach a high position.
Wheelchairs using an external power source (such as motor drive using a battery as the power source) for a stand-up mechanism have been proposed in recent years for a wheelchair which enables the user to do a work in a stand-up posture. However, the wheelchairs of this kind involve the drawbacks that the charging work and maintenance are complicated, that the weight of the wheelchair increases and that the wheelchair itself is extremely expensive with limited versatility.